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Gdańsk University of Technology

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Publications from the year 2014

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  • Implementation of failover and load balancing algorithms in SIP PBX High Availability system
    • Sylwester Kaczmarek
    • Jacek Andrzej Litka
    • Maciej Krajewski
    2014

    Goal of the project was to design a High Availability SIP VoIP system that guarantees access to additional services like auto-attendent and automatic call distribution. The realization of the project required system to have load balancing and failover algorithms implemented. From the end users’ point of view the whole system had to figure as a single element. After taking under consideration the known methods of implementations of the HA systems, a new method has been developed and implemented. The whole system had to be immune to outage of each of the elements it consists of. There was a necessity to make the system an elastic solution with availability to add additional redundant elements in a way that required a little to no additional works with its algorithms. The last requirement was to make the system immune to the changes in its structure made by sudden outages and recovers of impacted elements. Each of the elements that recovered after the outage ought to regain all the data shared by the rest of the elements. System worked with the use of programs: Asterisk, Heartbeat and Kamailio. The whole system consists of five virtual computer platforms, set on a single physical PC. Two Kamailio servers and three Asterisk servers where the basis for the system. Kamailio was set to work as a dispatcher which assignment was to load balance the traffic between media servers. The second task of Kamailio servers was authentication of the end users. The last function was to find out outages of media servers in the system and reassign the destination media server for SIP traffic in case of its outage. Asterisk servers were the source of additional services guaranteed to the end users. Asterisk was also responsible for the dialplan for the users. Heartbeat worked on Kamailio platforms and its task was to failover between them in case of active Kamailio server’s disconnection. It also assigned virtual IP address to the active dispatcher which was used as a destination address for end users registration process. The scope of the tests undertaken for this solution was to examine the required functionality. Failover process for both Kamailio and Asterisk servers were tested, as well as load balancing algorithm. Additional tests included checking if a recently disconnected media server recovers all the data shared amongst other media servers and the communication process between system’s elements in some of the most basic SIP transactions scenarios.

  • Implementing Virtual Engineering Objects (VEO) with the Set of Experience Knowledge Structure (SOEKS)
    • Syed Imran Snafiq
    • Cesar Sanin
    • Edward Szczerbicki
    • Carlos Toro
    2014 Full text Procedia Computer Science

    This paper illustrates the idea of Virtual Engineering Object (VEO) powered by Set of Experience Knowledge Structure (SOEKS) and Decisional DNA (DDNA). A VEO is the knowledge representation of an engineering object, having embodiment of all its associated knowledge and experience within it. Moreover, VEO is a specialization of Cyber-Physical System (CPS) in terms of that its extension in knowledge gathering and reuse, whereas CPS is only aimed towards data and information management. The SOEKS/DDNA is a flexible and standard knowledge representation structure to acquire and store experiential knowledge. The article also presents a case study to demonstrate implementation of VEO in the manufacturing scenario. The decision making in industrial design and manufacturing will benefit from this approach, as it includes capturing, storage and reuse of experience and knowledge of an engineering artefact.

  • Improvement of derivatized amino acid detection sensitivity in micellar electrokinetic capillary chromatography by means of acid-induced pH-mediated stacking technique
    • Szymon Dziomba
    • Adrian Bekasiewicz
    • Adam Prahl
    • Tomasz Baczek
    • Piotr Kowalski
    2014 Full text ANALYTICAL AND BIOANALYTICAL CHEMISTRY

    Derivatization is a frequently used sample prepara-tion procedure applicable to the enhancement of analyte de-tection sensitivity. Amino acids mostly require derivatization prior to electrophoretic or chromatographic analysis, especial-ly if spectrophotometric detection is used. This study presents an on-line preconcentration technique for derivatized amino acids. The sensitivity of the method was improved by the utilization of the proposed acid-induced pH-mediated stacking mechanism. The method is demonstrated by preconcentration of amino acids labeled with 2,4-dinitrofluorobenzene. Use of optimized conditions for a large sample volume injection (40 s, 13.8 kPa) followed by electrokinetic injection of 0.1 M HCl (20 s, 10 kV) gave a 20- to 30-fold enhancement of sensitivity. The significance of the sweeping mechanism and pseudo-isotachophoresis for the on-line sample focusing and the influence of parameters on the preconcentration pro-cess were discussed. The applicability of the elaborated meth-od was demons ated using human urine samples.

  • IMPROVING THE QUALITY OF EDUCATION THROUGH THE IMPLEMENTATION OF THE DIPLOMAS AND GROUP PROJECTS DURING ENGINEERING STUDIES IN COOPERATION WITH EMPLOYERS
    • Artur Janowski
    • Agnieszka Jurkowska
    • Marek Przyborski
    • Anna Sobieraj-Żłobińska
    • Jakub Szulwic
    • Dominika Wróblewska
    • B. Wieczorek
    2014

    The quality of education is one of the most important factors determining the job opportunity for graduates. The authors present the possibility of carrying out the diplomas in cooperation with employers and institutions interested in employment of students who graduated Gdansk University of Technology, Faculty of Civil and Environmental Engineering and University of Warmia and Mazury, Faculty of Geodesy and Land Management (major: engineering geodesy and cartography). Based on experiences it was possible to present problems which appeared during work on diplomas in cooperation with potential employers. There was also a situation of undoubted advantages for students towards gaining experience and employment prospects.In this study, the authors cite interesting solutions for better competitiveness in European labour market carried out by students. Problems associated with exclusion of young people from the labour market as well as suggestions to prevent such exclusion by the closer cooperation with potential employers are also indicated.

  • IMPROVING THE QUALITY OF EDUCATION THROUGH THE IMPLEMENTATION OF THE DIPLOMAS AND GROUP PROJECTS DURING ENGINEERING STUDIES IN COOPERATION WITH EMPLOYERS
    • Artur Janowski
    • Agnieszka Jurkowska
    • Marek Przyborski
    • Anna Sobieraj-Żłobińska
    • Jakub Szulwic
    • Dominika Wróblewska
    • Beata Wieczorek
    2014

    The quality of education is one of most important factors determining the job opportunity for graduates. The authors present the possibility of carrying out the diplomas in cooperation with employers and institutions interested in employment of students who graduated Gdansk University of Technology, Faculty of Civil and Environmental Engineering and University of Warmia and Mazury, Faculty of Geodesy and Land Management (major: engineering geodesy and cartography). Based on experiences, problems which appeared during work on diplomas in cooperation with potential employers were presented. That was also a situation of undoubted advantages for students towards gaining experience and employment prospects. In this study the authors cite interesting solutions for better competitiveness in European job market carried out by students. Problems associated with exclusion of young people from the labour market as well as suggestions to prevent such exclusion through closer cooperation with potential employers are also indicated.

  • In vitro evaluation of novel lipopeptides with potential therapeutic application
    • Monika Kukowska
    • Krystyna Dzierzbicka
    • Wioleta Januchta
    2014 JOURNAL OF PEPTIDE SCIENCE

    The synthesis of derivatives of Gly-His-Lys was elaborated followed by their antimicrobial activity investigation.

  • In Vitro Studies on the Relationship Between the Antioxidant Activities of Some Berry Extracts and Their Binding Properties to Serum Albumin
    • Jacek Namieśnik
    • Kann Vearasilp
    • Alina Nemirovski
    • Hanna Leontowicz
    • Maria Leontowicz
    • Alma Leticia Martinez-Ayala
    • Gustavo Gonzalez-Aquilar
    • Milan Suhaj
    • Shela Gorinstein
    2014 Full text APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY

    The aim of this study was to investigate the possibility to use the bioactive components from cape gooseberry (Physalis peruviana), blueberry (Vaccinium corymbosum), and cranberry (Vaccinium macrocarpon) extracts as a novel source against oxidation in food supplementation. The quantitative analysis of bioactive compounds (polyphenols, flavonoids, flavanols, carotenoids, and chlorophyll) was based on radical scavenging spectrophometric assays and mass spectrometry. The total phenolic content was the highest (P<0.05) in water extract of blueberries (46.6±4.2 mg GAE/g DW). The highest antioxidant activities by 2,2- diphenyl-1-picrylhydrazyl radical scavenging assay and Cupric reducing antioxidant capacity were in water extracts of blueberries, showing 108.1±7.2 and 131.1±9.6 μMTE/g DW with correlation coefficients of 0.9918 and 0.9925, and by β-carotene linoleate assay at 80.1±6.6 % with correlation coefficient of 0.9909, respectively.

  • IN VIVO DEGRADATION OF BIOMATERIALS
    • Beata Świeczko-Żurek
    2014

    The material designed to be introduced into the human tissue should be biocompatible and biofunctional. Unless it is so, the body may respond to the implant in different ways. An inflammation reaction may appear such as: parting of items of the implant surface resulting from fraction or pressure. The condition of the surface has an important influence on the usefulness of the implant. The required values depend on the implant function and the material the implant is made of. In implants the main requirement is corrosion resistance. There should be no permanent connection between the implant and the bone. All biomaterials are subjected to degradation. Therefore it is essential, that degradation products should not cause any harmful effects such as inflammation and that there is a possibility of fast removal of the implant from the organism. Different kinds of implants, which underwent degradation, were taken out from the body and examined

  • Inbound marketing a skuteczna komunikacja marketingowa
    • Magdalena Brzozowska-Woś
    2014 MARKETING I RYNEK

    Celem artykułu jest ukazanie koncepcji inbound marketing jako przykładu nowego podejścia do planowania i realizacji polityki komunikacji marketingowej w Internecie. Współcześnie klienci nie chcą być atakowani nachalną reklamą lub zanudzani przez nieatrakcyjne treści. Odwracają się od marek, które prowadzą z nimi komunikację jedynie przy użyciu tradycyjnych działań komunikacji marketingowej. Znane organizacje wykorzystują do promowania swoich marek inbound marketing (IM). IM oferuje efektywny kosztowo i wymierny sposób generowania większej liczby użytkowników oraz skłania do realizacji większej liczby zakupów niż tradycyjne działania komunikacji marketingowej. Działania IM kierują uwagę nabywców bezpośrednio na strony witryny internetowej organizacji, szczególnie gdy są oni zainteresowani odnalezieniem rozwiązania istotnego dla nich problemu. IM opiera się na trzech głównych komponentach: wyszukiwarki internetowe, kontent, media społecznościowe. Ciekawe treści napędzają ruch na stronach naszej witryny internetowej oraz zwiększają liczbę potencjalnych klientów. IM tworzy wiarygodność i szacunek, pozwalając nam zdystansować naszą konkurencję.

  • Increasing the Efficiency of Ontology Alignment by Tracking Changes in Ontology Evolution
    • Marcin PIetranik
    • Ngoc Thanh Nguyen
    • Cezary Orłowski
    2014 LECTURE NOTES IN COMPUTER SCIENCE

    In this paper we present a development of our ontology alignment framework based on varying semantics of attributes. Emphasising the analysis of explicitly given descriptions of how attributes change meanings they entail while being included within different concepts have been proved useful. Moreover, we claim that it is consistent with the intuitive way how people see the real world and how they find similarities and correspondences between its elements. In this paper we concentrate on the issue of tracking changes that may occur within aligned ontologies and how these potential changes can influence the process of finding new mappings or validating ones that have already been found.

  • Indeks jakości powietrza
    • Michalina Bielawska
    • Waldemar Wardencki
    2014 Analityka: Nauka i Praktyka

    W artykule przedstawiono użyteczne narzędzie do przekazywania informacji na temat poziomu zanieczyszczęń powietrza opinii publicznej za pośrednictwem mediów i internetu - indeks jakości powietrza. Kolejno przedstawiono; historię indeksu jakości powietrza, metodykę jego wyznaczania i przykłady zastosowań w monitoringu powietrza.

  • INDIRECT CONTROL OVER SUBORDINATE UNITS
    • Bartosz Jakusz
    • Przemysław Kulesza
    • Michał Wójcik
    2014 Zeszyty Naukowe Wydziału ETI Politechniki Gdańskiej. Technologie Informacyjne

    Developing a game universe usually involves creation of various units which can be both, encountered by a player or controlled by him. There is a number of works considering autonomous behaviors of units wandering around the game world. When it comes to the units controlled by the player, they are often deprived of autonomy and are strictly controlled by the player. This paper presents a concept of units behavior depending on their inner state, where player can only give orders, make request and proposal which result cannot be strictly predicted.

  • Indirect Measurement of Motor Current Derivatives in PMSM Sensorless Drives
    • Leszek Jarzębowicz
    2014 Full text Elektronika Ir Elektrotechnika

    Motor current derivatives contain useful information for control algorithms, especially in sensorless electric drives. The measurement of motor current derivatives in electric motors supplied by voltage source inverter can be performed using di/dt transducers. However, in such a solution additional sensors have to be installed, e.g. Rogowski coils. Another approach is to measure current derivatives indirectly – by oversampling the motor currents. In such a method special attention must be paid to determination of current sampling instants. Measurement triggering times must be recalculated in each voltage modulation period with regard to transistors switching. The paper presents different current sampling approaches. Considered oversampling algorithms were experimentally tested in sensorless PMSM drive. The impact of different sampling approaches on the accuracy of rotor position estimation has been discussed.

  • Induced Sheath Voltages In 110 Kv Power Cables – Case Study
    • Stanisław Czapp
    • Krzysztof Dobrzyński
    • Jacek Klucznik
    • Zbigniew Lubośny
    2014

    The paper considers shock hazard due to induced sheath voltages in 110 kV power cables. Various configurations of the metallic sheaths bonding and earthing (single-point bonding, both-ends bonding, cross-bonding) are analysed. Taking into account shock hazard and ability of the system to power transfer an optimal configuration is proposed.

  • Induced-fit binding of laccase to gold and carbon electrodes for the biological fuel cell applications
    • Maciej Karaskiewicz
    • Dominika Majdecka
    • Agnieszka Wieckowska
    • Jan Biernat
    • Jerzy Rogalski
    • Renata Bilewicz
    2014 ELECTROCHIMICA ACTA

    Analogues of laccase natural substrates (syringic, veratric, ferulic, vanillic, isovanillic, 3,5-dimethoxybenzoic aldehydes) were employed to bind and orient laccase molecules in a way which facilitates adsorption of the catalyst molecules and their electrical connection with the conductive support. Laccase was bound efficiently to these substrates both on gold and carbon electrodes forming, respectively, 2D and 3D films sensitive to oxygen. Gold electrodes were used for the surface plasmon resonance evaluation of the extent of laccase binding. Glassy carbon electrodes covered with single-wall carbon nanotubes (SWCNTs) covalently modified with laccase were shown to lead to higher catalytic reduction currents than the bare carbon nanotubes deposited in a similar film at the electrode. SWCNTs with ferulic group chosen for the practical application of the biocathode in the air-zinc biobattery allowed to improve its performance both in terms of power and stability in time. The open circuit potential of the cell was 1.71 ± 0.05 V and the maximum power density achieved was 5.1 mW/cm2 at 0.6 V

  • Indykatory mobilne GIS w analizie ruchu miejskiego
    • Artur Janowski
    • Jakub Szulwic
    2014 Full text Logistyka

    W ramach artykułu autorzy przedstawią możliwości monitorowania sytuacji komunikacyjnej miasta z wykorzystaniem autorskiego i dedykowanego systemu monitorowania ruchu w mieście, opartego o pakiet oprogramowania stacjonarnego i mobilnego przeznaczonego dla korporacji taxi. Celem publikacji jest przedstawienie założeń optymalnych i minimalnych do realizacji monitoringu ruchu w mieście. Przywołane zostaną autorskie próby wdrożeń rozwiązań w Olsztynie (Polska) i możliwe do implementacji jako weryfikujący lub uzupełniający dla skomplikowanych i wysokokosztowych systemów zarządzania transportem oraz monitorowania przepustowości ulic miejskich. Wg analiz wykonanych przez autorów system oparty na indykatorach mobilnych, implementowanych w nieuprzywilejowanych pojazdach pozwala skutecznie analizować sytuację transportową miasta. Dodatkowo dane pozyskane z ulic miasta są wzbogacone danymi georeferencyjnymi, dzięki czemu możliwe jest wsparcie analiz koniecznych dla rozwoju miast (sieci transportowe, sieci drogowe, utrudnienia i niemożliwości przejazdu oraz wskazanie fakultatywnych i zastępczych dróg przejazdu).

  • Indywidualne projektowanie nawierzchni
    • Bohdan Dołżycki
    • Józef Judycki
    • Piotr Jaskuła
    2014

    Analityczne opracowanie wyjaśniające zasady weryfikacji i aktualizacji obliczeń zawartych w nowym katalogu typowych konstrukcji nawierzchni podatnych i półsztywnych z 2013 roku dostosowanym do współczesnych technologii i materiałów, zwiększonego obciążenia dróg przez ruch drogowy, zmienionych sposobów wzmacniania podłoża, recyklingu materiałów drogowych, ujednoliconego nazewnictwa warstw konstrukcji nawierzchni oraz nowych metod obliczeń konstrukcji nawierzchni. Zawiera również porównanie katalogów typowych nawierzchni z Austrii, Francji, Niemiec i Wielkiej Brytanii z katalogiem polskim.

  • INFLUENCE OF BISMUTH CONTENT ON COMPLEX IMMITTANCE CHARACTERISTICS OF PRESSURELESS SINTERED BiNbO4 CERAMICS
    • Dionizy Czekaj
    • Agata Lisińska-Czekaj
    • Małgorzata Adamczyk
    2014 Full text ARCHIVES OF METALLURGY AND MATERIALS

    Goal of the present research was to study immittance properties of BiNbO4 ceramics fabricated by the solid state reaction route followed by pressureless sintering. Four sets of samples were examined, namely the one fabricated from the stoichiometric mixture of oxides, viz. Bi2O3 and Nb2O5 as well as the ones with an excess of 3%, 5% and 10% by mole of Bi2O3. The immittance properties were studied by impedance spectroscopy. Measurements were carried out within the frequency range =20Hz-1MHz and temperature range T =RT-550C. The Kramers-Kronig data validation test was employed in the impedance data analysis. It was found that complex impedance first increases with an increase in Bi2O3 content and decreases for 10mol% excess of Bi2O3. Two relaxation phenomena manifested themselves at elevated temperature (T>267C) within the measuring frequency range. The conductivity relaxation phenomenon (M00() spectra) took place at higher frequency than the phenomenon with dominant resistive component (Z00() spectra).

  • Influence of compaction effectiveness on interlayer bonding of asphalt layers
    • Piotr Jaskuła
    2014

    The paper presents the results of research on the interlayer bonding of asphalt layers compacted in the laboratory and in the field. To measure the interlayer bonding at a temperature of 20°C the Leutner test apparatus was used and load was applied at a rate of 50 mm/minute. Three types of interlayer interfaces were tested: no tack coat and tack coats made of two types of the pure bitumen emulsions. Four compaction techniques were used in laboratory conditions: rolling with and without vibrations, gyratory compaction and compaction with slab compactor, including both hot-to-cold and hot-to-hot. The fields specimens cored from pavements differed in terms of relative compaction. It was found out that interlayer bond strength between the layers of asphalt dependeds strongly on the applied compaction technique, as well as the compaction effort. In some cases efficient compaction produced a maximum shear force without tack coat. The type of emulsion used as the tack coat was also found to be highly relevant to the interlayer bonding.

  • Influence of dipoles on the recombination in organic photovoltaic devices
    • Jędrzej Szmytkowski
    2014

    Although organic compounds are promising materials to use them in photovoltaic devices, the efficiencies of organic solar cells are still lower in comparison to inorganic photocells. The recombination of charge carriers leads to the loss of photocurrent, therefore a detailed theoretical description of this process is required. In the present work, an influence of interface dipoles on the recombination process is discussed. We show how electrical dipoles cause the reduction of nongeminate recombination in organic bulk heterojunction solar cells.